Telephone system.



No. 877,058. PATENTBD JAN. 21, 1908.

W. W. DEAN.

TELEPHONE SYSTEM.

ArrLloA'rxon rILnn nov.11,19oa.

UNITED STATES PATENT OFFICE.

WILLIAlil W. DEAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Panama Je... 21, 190e.

Application filed November 11. 1903. Serial No. 180.687.

To all whom it may concern:

Be it known that I, WiLLIAM W. DEAN, a citizen of the United States of America, and resident of Chica yo, countyof Cook, and State of Illinois, iave invented a new and useful Im rovement in Telephone Systems, of which t ie following is a specification.

My invention relates to telephone systems and particularly to systems of a common battery type in which two sources of current are sup lied at the central oilice, said sources eing employed for each conversation.

One object of the invention is to provide means in connection with such systems whereby when connection is established with a calling subseribers line the potential upon the line is not greatly varied so that practicall no noise is caused in the waiting subscri er's receiver, and other objects are to provide a simplified circuit arrangement and apparatus which is convenient and inexpensive.

My invention is illustrated in the accompanying drawin in which the figure is a dial gram oi a telep one system embodying m improvements and in-which L and L indicate subscribers lines extending in two limbs 2 and 3 from their respective substations A and D to the central oflice C where they are fitted with the usual line signals S, answering jacks and multiple jacks such as J2 and Ja in anyr number, accordi r to the size of the switchboard. The. sxiillistation outfit is diagrammatically represented by the ordinary signaling bell 4 and condenser 5 in a permanent bridge of the line conductors, and a transmitter 6 and receiver 7 in a second bridge, whose normal discontinuity is maintained by the switch hook 8. Any other substation device adapted for common battery actuation may be employed. At the central oiiice the line rela R is provided with a pair of windings 9 an 10, the former t' legged to ground from the sleeve line conductor 3 and the latter included in a conductor 11 extending from the tip line conductor to the armature of a polarized cut-oil relay it", whose windin f is included in said sleeve line conductor 3 lictween the line relay and the jacks. The normal contacts of the said cut-oill relay consists of the springs l2 and 13 normally resting against suitable stops 14 and 15, the latter being employed as a normal contact for its spring 13. The spring 14 is connected by conductor 16 with thc coninion battery lead 17 connected with the livc pole of the central common battery l, whilc the forward contact of the said cut-oil' rclay is joined by conductor 18 with the battery lead 19 connected with the live pole of the second common battery B2. The said contact of said s ring 13 is connected by a conductor 2() witli one side of the line signal S, while the other side of the signal S is connected by a wire .21 with thc spring of thc line relay It, the forward contact oi which is cWounded. The armature of said cut-oil rclaav is shown in its normal iosition, but the relay is so polarized that wllien current iiows through it in one direction, the armature will be tipped to one side, and when current Hows through it in the other direction said armature will be tipped in the opposite direction. With the arrrangeinent and connections as shown in the diagram, said relay is polarized to respond to neeative current owing therethrough in the direction of the arrow so as to move its armature away from the springs l2 and 13 and bring it into cngagement with the contact of conductor 18 when current iows through it in the opposite direction the armature is moved in the opposite direction to lift said springs 12 and 13 and separate spring 13 from its normal contact 15.

The operators are provided with a plurality of cord circuits, each having an ansu'cring plug P and a calling plug l"- provided 'with tip and sleeve contacts adaptcd to rcgister with the corresponding contacts` ofthe jacks, the tip contacts oi' said plugs bcing connected by the ilcxiblc strands t and t'5 and the interposed condenser c, while thc sleeve contacts are joincd by similar strands 8 and s and the interposed condcuscr c. pair of supervisory relays r and l'2 arc nidged across the answering cnd ol' thc cord circuit and together control the local circuit of the supervisory signal S associatcd with the answering ilug, thc i'orincr rcla scrving when energized to opcn said circuit and thc latter to close the saine. Au intcroicdiatc point of the bridgt` ol thcsc rclai's is ioincd )y a conductor .Z. with thc battery lcad It. A similar pair of relays 1"" and r arc bridgcd across the calling cnd of thc cord circuit and control in like manner thc local circuit ol' tht` su iervisory sivnal Slz associatcd with thc ca ling plug` tlic intermediatel point. ol' said supervisory bridge heilig joined by a suitable conductor 23 with the live pole of the said battery B. 'lhe operatoi"s head telephone 24, the secondary of liei induction coil 25, and a suit-able condenser c are. adapted to be bridged across the calling end of the. cord circuit by the o )eration of any siitable. listening key, sucfi as 26, her tiansiiiitter 27 and the )riinary of hei' induction coil being charged lrom any suitable source of current and which ina f be either the battery B or B'-. A suitabfe high resistance and high impedance test relay 1"" is adapted to be connected by the spring 2S of the listening key and through conductor 9 with the forward portion of the strand t of the cord circuit by means of the extra spring 3() upon the stipervisory relay 1*, said spring serving when the said relay is energized to complete the strand t2 for conversation. The ringing generator 3l is adapted to be connected with the tip side. of the cord circuit when the ringing key 32 is o ieiatcd, the sleeve side of the cord circuit being simultaneously connected with batterv lead 17 by the conductor 33.

1n t ie operation of my invention the subscriber A taking u his receiver coin )letes a path for current from the battery ii, over conductors 17 and 16, spring 12, the arinature of cut-oi relay R2, conductor 11, winding 1t) of line. relay lt, line conductor .Z, through thev substation devices and back to the central office over line conductor 3 and through the winding t) of the line relay R to ground. '1`he current in this path actuates the line relay it to close the. local circuit of the. line signal S, said circuit. heilig traced from the battery lead 17 over conductor 16, spring 14 of cut-off relay W, armature of said relay, spring 13, cont-act 15 and conductor .20 of one terminal of the lamp, and thence over conductor 21 to the spring and forward contact of the line relay lt to ground. Upon observing this signal the operator inserts the answering plug IS` of her cord circuit., thereby completing a path for current froin the battery 15"', ovei conductois 19 and 22, throueh the sleeve supervisory relay, sleeve strain s of the cord circuit and over coiidtictor 3, through the polarized cut-oil' relay lt'l and the winding t) of the line relay to ground. 'l he current in this path is of such direction that the springs l2 and 13 of the saine are lifted froin the stop 14 and contact l5, thereby opening at the latter contact the local circuit of the line signal S and ietiriiig the sinne. 'l`he connection with the battery B, however, is maintained between the spring 12 and the armature of the cut-oil' relay, so that during the connection such battery continues to furnish current. over the telephone line. 1`he actuation of the sleeve supervisory relay 1' closes the circuit of the supervisory signal S" but the simultaneous operation of the supervisory ielay r over the tip side of the telephone line opens said circuit and prevents the signal glowing. l'pon learning the order of the calling subscriber the line is tested in the usual manner by touching tht` tip of the calling plug to one of the test rings of the jacks of said line. Said test rings are normally grounded through the winding.) of the line relay it and since the operat.oi"s key is now actuated and the supervisory relay r is not yet. actuated the tip ofthe calling plug P'" is likewise grounded so that no tlow of current takes place and the operatorknows that. the line is idle. ln case the. line is engaged, the sleeve rings are connected through the sleeve strand of thc inserted plug with the live pole of either the battery B or B'l and the. application of the grounded tip of the plug thereto results in a flow of current through the test relay r" which closes tht` local circuit through the operator`s induction coil and causes ii click in hei` receiver, thus notifying heil that the line is busy Assuming that. the line is idle, the calling plug P2 is inserted and the ringing .key 3'.) de pressed. rl`he insertion of the calling plug in t-he first place closes a path for current from the negative pole of the battery B over conductors 17 and 23, through the sleeve super- Visory relay if, sleeve strand s`- of the cord circuit and the sleeve conductor 3 of the tele phone line and thence through the. winding n of the cut-off relay to ground. This current, it will be observed, is of the proper direction t0 tip the armature of said cut-oil` relay in the opposite direction from that of the line L, thereby opening at spring 13 the local cir-l cuit of the line signal S and disconnecting at spring l2 lthe battery B, and connecting said armature through conductors 18 and 1S) with the battery B2. Theo )eration of the ringing key serves to connect the generator 31 in the metallic. line and to connect the sleeve side of the line around a supervisory relay r by n'ieans of conductor 33 with said battery lead 17. Thus the said cut-off relay is now maintained actuated in the saine direction during rin ring. After the subscriber has been cal ed but before his response the supervisory rela r is actuated to close. the local circuit of t ie supervisory signal S, thereby lighting the sinne, as well as to disconnect. the conductor 2t) leading to thc test relay and coinpleting the strand t of the cord circuit. for conversation. Upon the. subscribens response., the tip supervisory relay 1'" receives current in thel inanner described for the similar relay rand serves to open thc local circuit of the supervisory signal S to retire the saine, thus indicating to the operator that the subscribers are connected for conversation. During conversation the battery l is furnishing current. toithe line. l. and the battery B'2 is furnishing current to the line li. The lilies are thus independently siippiied by connection is established `with a calling tele-` phone' line to thereby inoperative,

to disconnect said source lwith a plurality of sources of current at the central office with with the battery B during the process of making the connection, remains undisturbed by changes of potential on the line,

, Having thusdescribed my in v'ention, what i I claim is .z

1. In a telephone system, the-combination with a plurality of'telephone lines, of a pair of sources of current at'the central office with one of which said lines' are normally connect'- ed, a cut-off relay for eachline, means for operatingsaid relay in one direction when a render theline signal lnoperative, the connection with said source of current remaining undisturbed at this time, and further means for o 'erating said relay in the reverse direction w en a connection is established with ay called telephone line to render the line signal inoperative and of current, substantially as described.

2. In a telephonesystem, the combination of telephone lines,. of a p air one'of which said lines are normally connected, a cut-0E relay foreach line, means for operating said relay in one direction when a connection is established with a calling telehone line to thereby render the line signal the connection with said source of ycurrent remaining undisturbed atjl this time, and further means for operating .said` relay in the reverse direction when a connec-- tion is established with a called telephone line to render the said line signal inoperative to disconnect said normal current sourceand tov connect said second source therewith, substantially as described. 3. In a telephone system, the combination with a plurality of telephone lines, of a pair of sources of current at the central office, one of said sources being normally connected with the lines to permit the` subscribers to call the central office, a polarized cut-olf relay for each line, andmeans controlled by said .cubed relays when connections are established with thelines so that the normal connection of the calling subscriber `with said current source remains undisturbed but the called subscribers line is disconnected therefrom, substantially as describedr 4. In a telephone system, the combination with a pluralityof telephone lines, of a pair of sources of current at the central office, one of said sources being normally connected with the lines to enable the subscribers to call the i central office, av polarized cut-off relay for each line7 and means controlled by said relay and when connections are established with thelines so that the normal connection of the calling subscriber with said current source remains undisturbed. but when connection is established with the called line -the said other poleof-'tlie :other source,V and source, substantia I is differently source is disconnected therefrom and the other source is connected therewith, subf stantially as described.

5. In a telephone system, the combination with a plurality of telephone lines, of a pair of sources of current at the central voflice with one of which said lines are normally connected, apolarized cut-off relay foreach line,v

a cord circuit to establish connections between the lines for conversation, one end of said-cord circuit being' connected with one pole of one sourceandgthe other end with the Vmeans whereby when connection is established by the cord circuit with the lines the cut-od relays of the calling lines permit said first named source to remain in 'connection with such lines while with the called-for lines the cut-0H relays are o perated to disconnect said 'y as described.

6. In a telephone system, the combination with aplurality oftelephone lines, of` a pair of sources of current at the central office with one of which said lines are normally connected a polarized cut-off relay for each line, a cord, circuit to establish connections between the lines for conversation one end of said cord source and of the other source, and means whereby when connection is established by the cord circuit with the linesI the cut-0H relays of the calling lines permit said first namedsource to remain in connection with-such lines` while with the called-for lines the cut-off relays are operated to disconnectsaid source and to connect sai otfier source.

,7. In a telephone system, the combination with a pair of telephone lines, mechanism for each line at thecentral office, a cord circuit to connect the lines together for conversation, means for sending' v'current through said switchingy mechanism in one directioniwhe'n the line is a calling line and in the opposite direction when the lineis a called line, whereby said lineswitcliing mechanism aected to differently control the circuits of the calling and called telephone lines, substantially as described.

8. In a telephone system, the combination with a cord circuit adapted together for conversation, of two sources of current for said cord circuit, sw itching mechanism associated with the lines, and means to dierently affect -said switching mechanism, whereby current is sent over like branches of said lines in opposite directions, substantiall as described.

9. In a te ephoner system, the combination with a cord circuit adapted to connect lines together for conversation, of two sources of current for said cord circuit, switching mechanism associated with the lines and means to differently affect said line switching mechanism, whereby current is' sent over like circuit being connected with one pole of one.

the other end with the vother pole ofswitching 4 to connect lines branches of said lines in opposite directions from said two sources, substantially as described.

10. In a telephone system, the combination'with a plurality of tele l hone lines,.a centralsource of current to w ich said lines are normally connected for signaling purposes, a polarized line switchinA device associated with each line and contro ing the connection of the lines with said source, a cord circuit, means to sen'd current through said polarized switching device in the lpro er direction to maintain the connection of t eline with said source when the answering end 'of said cord circuit is connected with said line, a second source of current, and means to send current ythrough said line switching device in the v WILLIAM W. DEAN.

Witnesses:

GAZELLE BEBER, E, A. GAsLocK. 

